Mix the water and starter until combined
Add flours and salt. Mix for 30-60 seconds by hand.
Let rest one hour
Mix again by hand, folding over onto itself.
Either let rest at room temperature for 8-12 hours OR refrigerate overnight.
Oil two 9x5 loaf pans.
Gently deflate and divide into two equal pieces on a floured surface. Fold and knead gently to form into loaves.
Put into loaf pans and cover with oiled plastic wrap for 1-2 hours until risen 1" above the lip of the pan.
Heat oven to 375°F. If you have a convection oven 350°F convection.
Put a metal baking dish or sheet pan low in the oven and add water or ice cubes. (Why ice cubes? Because they're easier to move around without spilling -- a trick I learned from someone online and am a big fan of.)
Slash the top of the loaves 2-3 times.
Bake for 45 minutes, turning 180° half way through.
Internal temperature of the loaves should be 190°F when done.
Let cook in loaf pans for 10-15 minutes before removing and letting cool on cooling racks. (For a crustier crust, remove from pans immediately and return to oven, turn oven off, and prop door open with a wooden spoon.)